The present invention relates generally to a donor blood sampling system.
It is known that approximately 0.1-0.3% of donated blood units are bacterially contaminated. Although this percentage is much higher than blood contaminated by viruses, such as HIV, nevertheless no routine test is currently performed to detect bacterial contamination. This poses a serious problem because a severely contaminated blood unit can cause sepsis in a recipient.
In general, blood is sampled from the vein for viral contamination-testing and typing after completion of donation. However, it is generally believed that the bacterial contamination stems from skin-embedded bacteria inaccessible to the sanitizing agents normally used before venipuncture. Therefore, systems have already been proposed in the prior art wherein a first volume of blood, typically in the order of 25-50 ml, is sampled to determine blood type and to detect for the presence of viruses. The sampling volume washes away most of the bacterial contamination before the blood is collected in the donor bag. Such a system should satisfy the following criteria:
1. The sampled blood should not be anticoagulated.
2. The collected blood must be anticoagulated.
3. Neither the donor nor collected blood should be exposed to the atmosphere during sampling.
4. The system should be simple and user friendly.
FIG. 1 illustrates a prior art predonation system, commercially available from NPBI, Netherlands. This system includes a small sampling bag 10 (with a volume of 30-50 ml) attached to a tubing branch 12 connected via a Y-connector 14 between a donor needle 16, attached to an upstream tube 32, and a main collection bag 18. Satellite bags 17 and 19 may be connected to bag 18 for processing the blood after collection. A needle 20 is attached to the distal side of sampling bag 10 through which blood is withdrawn while the rest of the system is isolated therefrom by means of external clamps 22 on tubing branch 12 and a donor tube 24 leading to main collection bag 18.
As stated above, the sampled blood should not be anticoagulated, whereas the collected blood must be anticoagulated. Accordingly, an anticoagulant used in collection bag 18 must be prevented from entering sampling bag 10. This means that tubing branch 12 must be sealed at all times before donation. This is achieved by means of a breakaway cannula 26 which is an externally openable closure in tubing branch 12 leading to sampling bag 10.
In the prior art system, the following steps are performed:
1. Clamp donor tube 24.
2. Break breakaway cannula 26.
3. Perform venipuncture and collect first blood in sampling bag 10.
4. Clamp tubing branch 12.
5. Open donor tube clamp 22.
6. Collect blood in main bag 18.
7. Connect a vacuum tube holder to needle 20.
8. Sample blood from sampling bag 10.
Another prior art system that operates in a similar manner is commercially available from Macopharma, France. Although the prior art systems approximately satisfy the four criteria mentioned hereinabove, nevertheless, they are labor intensive and cumbersome.
The present invention seeks to provide a simple, inexpensive and very easy-to-use donor blood sampling system which solves the abovementioned problems of the prior art.
In contrast to the prior art, in the present invention, the donor tube and tubing branch are preferably connected to the tube leading to the donor needle via a unique flow controller. The flow controller provides simple, straightforward blood flow control. The flow controller has only two operating positions. In a first position, this being the position in which the system is provided to the end-user, blood can flow to the sampling bag via the tubing branch, and the donor tube is substantially sealed from blood flowing therein. A user can place the flow controller into a second position, wherein blood can flow to the main collection bag via the donor tube, and the tubing branch is substantially sealed from blood flowing therein. In the present invention, not one drop of sampled blood flows towards the collection bag and no anticoagulant agent can contaminate the sampling bag. Neither the donor nor collected blood is ever exposed to the atmosphere during sampling. The system is very simple and user friendly.
There is thus provided in accordance with a preferred embodiment of the present invention a donor blood sampling system including sampling apparatus attached to a tubing branch, a donor needle attached to an upstream tube, the donor needle being adapted for drawing blood from a body, and a main collection bag attached to a donor tube, characterized by a flow controller including an inlet flow member including an inlet port connected to the upstream tube, and an outlet flow member connected to the inlet flow member and including a first outlet port connected to the tubing branch, and a second outlet port connected to the donor tube, the flow controller having a first position and a second position, wherein in the first position, blood can flow to the sampling apparatus via the first outlet port and the tubing branch, the second outlet port and the donor tube being substantially sealed from blood flowing therein, and wherein in the second position, blood can flow to the main collection bag via the second outlet port and the donor tube, the first outlet port and the tubing branch being substantially sealed from blood flowing therein.
In accordance with a preferred embodiment of the present invention a seal is positioned between the inlet flow and outlet flow members that substantially seals the outlet ports from each other.
In accordance with a preferred embodiment of the present invention the outlet flow member is arranged for rotation with respect to the inlet flow member between the first and second positions.
Further in accordance with a preferred embodiment of the present invention the inlet flow member includes a rim that extends from the inlet flow member, the rim defining a receiving volume inwards of a perimeter of the rim, and the outlet flow member sealingly and rotatingly sits in the receiving volume.
Still further in accordance with a preferred embodiment of the present invention the outlet ports are positioned generally symmetrically about a central axis of the flow controller and the inlet port is positioned offset from the central axis.
Additionally in accordance with a preferred embodiment of the present invention the seal includes an inner seal connected to an outer seal, wherein a central axis of the inner seal is offset from a central axis of the outer seal.
Still further in accordance with a preferred embodiment of the present invention the seal sits in a groove formed in the inlet flow member.
In accordance with a preferred embodiment of the present invention the seal is formed with a channel having two branches arranged for fluid communication with the inlet port and the outlet ports, wherein when one of the branches is in fluid communication with the inlet port and one of the outlet ports, the other branch is not in fluid communication with the other outlet port, thereby substantially preventing fluid flow to the other outlet port.
Further in accordance with a preferred embodiment of the present invention a volume-limiting clamp is clamped to the sampling bag.
In accordance with a preferred embodiment of the present invention the sampling apparatus includes a sampling bag.
In accordance with another preferred embodiment of the present invention the sampling apparatus includes a sampling device that clamps on the tubing branch and is operative to divert blood into a collection tube.
Further in accordance with a preferred embodiment of the present invention the flow controller includes a base formed with a pivot edge and pockets for receiving therein the tubing branch and the donor tube, and a lever pivotedly attached to the base about the pivot edge, the lever including a pair of protrusions that are arranged to press against and substantially seal one of the tubing branch and the donor tube.
Still further in accordance with a preferred embodiment of the present invention the lever includes a pair of lips adapted to fixedly snap onto ridges protruding from the base.